1. Field of the Invention
The present invention relates to fastener driving tools, particularly such tools in which the fasteners comprise nails. Thus, the tool according to the invention may comprise a nailer. However, the invention also concerns fastener driving tools for other types of fasteners, including pins, staples, etc.
2. Description of the Related Art
U.S. Pat. No. 4,042,036 discloses an impact tool having two flywheels arranged to propel an impact ram, to drive nails from the tool. Each flywheel is powered by its own respective motor, located adjacent thereto. One flywheel and its motor have a fixed rotational axis, whereas the other flywheel and its motor have a movable rotational axis which is arranged to pivot about an axis located on the opposite side of the motor/flywheel to that of the fixed motor/flywheel. The flywheel having a movable rotational axis can thus be moved toward and away from the other flywheel, to engage with, and disengage from, the ram.
U.S. Pat. No. 4,121,745 also discloses an impact tool having two flywheels arranged to propel an impact ram, to drive nails from the tool. A single mains powered AC electric motor powers both of the flywheels, by means of a belt which is driven by the rotor shaft of the motor. One of the flywheels has a fixed rotational axis, and the other flywheel has a movable rotational axis which allows that flywheel to be moved toward and away from the other flywheel, to engage with, and disengage from, the ram. The movable flywheel is pushed directly toward the fixed flywheel by means of a cam rod, and moves back directly away from the fixed flywheel under the influence of a compression spring.
U.S. Pat. No. 4,323,127 also discloses an impact tool having two flywheels arranged to propel an impact ram, to drive nails from the tool. Each flywheel is powered by a respective electric motor situated adjacent thereto, and each flywheel and its respective motor is pivotable about an axis located on the opposite side of the motor flywheel to that of the other motor flywheel. The flywheels and motors are pivoted toward each other by means of solenoids when the user pulls a trigger of the tool. The flywheels and motors pivot away from each other under the influence of springs.
U.S. Pat. No. 4,558,747 also discloses an impact tool having two flywheels arranged to propel an impact ram, to drive nails from the tool. A single motor powers both of the flywheels, by means of a gearing and pulley mechanism. Each flywheel is arranged to pivot toward and away from the other flywheel about a respective pivot point located such that a plane joining the pivot point and the rotational axis of the flywheel is approximately perpendicular to a plane in which the two axes of rotation of the flywheels lie.